Hooked: How to Build Habit-Forming Products

by Nir Eyal

As part of a French study, researchers wanted to know if they could influence how much money people handed to a total stranger asking for bus fare by using just a few specially encoded words. They discovered a technique so simple and effective it doubled the amount people gave. The turn of phrase has not only proven to increase how much bus fare people give, but has also been effective in boosting charitable donations and participation in voluntary surveys. In fact, a recent meta-analysis of forty-two studies involving over twenty-two thousand participants concluded that these few words, placed at the end of a request, are a highly effective way to gain compliance, doubling the likelihood of people saying yes.24 The magic words the researchers discovered? The phrase “But you are free to accept or refuse.”